CN102350421B - Force position servo control system for automatically cleaning carbon bowl of anode carbon block for aluminum electrolysis - Google Patents

Abstract

The invention discloses a force position servo control system for automatic cleaning of anode carbon block and carbon bowls for aluminum electrolysis, including five servo drive motors with absolute encoders, two pressure sensors, a torque sensor, and a programmable A controller, the programmable controller communicates with five servo drive motors through the field bus, and is connected with the pressure sensor and the torque sensor through the I/O port; It is a photoelectric switch for positioning the carbon block; it also includes a vision system for positioning the center of the carbon bowl and the angle of the chute of the carbon block; the programmable controller positions the cleaning tool to the center of the carbon block according to the position information obtained by the vision system. Charcoal bowl and chute, and control the cutter to clean the charcoal bowl and chute at the same time. It can realize the automatic force position servo control of anode carbon block positioning, anode carbon block height measurement, carbon bowl and chute positioning, and carbon bowl and chute cleaning.

Description

Force position servo control system to realize automatic cleaning of anode carbon block carbon bowl for aluminum electrolysis

technical field

The invention relates to an industrial servo control system, in particular to a force position servo control system for realizing automatic cleaning of anode carbon block carbon bowls for aluminum electrolysis.

Background technique

Domestic aluminum electrolytic aluminum electrolytic anode carbon blocks use petroleum coke as raw material, and undergo high-temperature calcination, kneading, molding, roasting and other processes to obtain roasted anode blocks. The carbon block is used as an anode to replace aluminum metal through electrolysis. The anode carbon block is shown in Figure 4. There are four blind holes on the upper surface of the carbon block with a diameter of about 170mm. The inner wall of the hole has a spiral groove with a rise angle of 75°. These blind holes are commonly called carbon bowls. Insert the conductive steel claw into the charcoal bowl and cast it firmly, then it can be sent to the electrolytic cell for use. The role of the spiral chute on the inner wall of the carbon bowl is to prevent the loose connection between the carbon block and the conductive steel claw.

During the roasting process of the anode carbon block, in order to avoid oxidation, a large number of carbon particles are laid around the anode carbon block for protection. After the roasting is completed, a large number of carbon particles will be bonded on the surface of the anode carbon block and in the carbon bowl and have a certain bonding strength. These carbon particles need to be cleaned before use. The current cleaning method for carbon blocks is to use a special shovel to shovel off the carbon particles on the surface of the carbon block and in the carbon bowl, and then blow them away with compressed air. Manual cleaning of the carbon blocks generally takes 2-3 times to meet the qualified requirements. , and the compressed air will make the carbon powder diffuse in the air, which makes the working environment of the carbon block cleaning harsh, the workload is large, the personnel mobility is large, and there are potential safety hazards.

Contents of the invention

The purpose of the present invention is to provide a force position servo control system for automatic cleaning of anode carbon block carbon bowls for aluminum electrolysis.

The purpose of the present invention is achieved through the following technical solutions:

The force position servo control system for automatic cleaning of anode carbon blocks and carbon bowls for aluminum electrolysis of the present invention includes five servo drive motors with absolute encoders, two pressure sensors, a torque sensor and a visual recognition software and hardware system. The five servo drive motors with their own absolute encoders are respectively spindle servo motors, chute servo motors, X-axis servo motors, Y-axis servo motors, and Z-axis servo motors;

It also includes a programmable controller, the programmable controller communicates with the five servo drive motors through the field bus, and is connected with the pressure sensor and the torque sensor through the I/O port; three of the five servo motors form three The degree of freedom Cartesian coordinate robot system is used to carry the cleaning tool and realize positioning, and the other two control the two kinds of tool movements on the cleaning tool separately;

It also includes a photoelectric switch installed at the starting position and end position of the carbon block for positioning the carbon block;

Also included is a vision system for positioning the center of the charcoal bowl and the angle of the chute for the charcoal block;

The cutting tool can be controlled to clean the charcoal bowl and the chute at the same time through the force-position mixing control method.

There are two photoelectric switches installed at the end position of the carbon block, which are used to detect the arrival and departure of the carbon block, so as to realize the cooperation with the working mode of the original production line.

The determination of the center of the charcoal bowl and the angular position of the chute is to use the vision system and image recognition software to obtain the coordinates, and then use the PLC to control the motor of the three-degree-of-freedom rectangular coordinate robot to search for the tool.

When the vision system obtains the coordinates of the charcoal bowl, it takes pictures of a single charcoal bowl separately, obtains the relative coordinates of the charcoal bowl, and then calculates the absolute coordinates with reference to the value of the servo motor encoder.

The control system searches for the position of the charcoal bowl using the method of descending under the condition of force limitation, that is, every time the tool moves one step during the search process, the tool descends to touch the carbon block, and stops after reaching a certain contact force. Whether the cutter is aligned with the center of the charcoal bowl and the position of the chute.

When the PLC controls the three-degree-of-freedom rectangular coordinate robot to search for the actual position of the center of the charcoal bowl, a grid-style traversal search method is adopted, that is, the calculation coordinates are used as the center to divide the grid, and the knife is tested in the X and Y directions with a fixed step. .

The measurement of the height of the carbon block is realized by using the tool to touch the carbon block, that is, the tool is pressed down and reads the data of the force sensor. When the tool is in contact with the upper surface of the carbon block, the height of the carbon block can be obtained through the encoder value of the Z-axis servo motor .

During the cutting process, the pressure in the vertical direction and the torsion of the chute knife are limited. The closed-loop PID control of the torque and the movement of the chute knife realizes the mixed control of force and position, so that the chute knife can automatically move along the direction of the chute during the cutting process. Rotate in the helical direction to realize simultaneous cleaning of the charcoal bowl and the chute.

It has a dual touch screen operation interface, in which the touch industrial computer display is used to operate the charcoal bowl photo recognition software and monitor the charcoal bowl situation, and the industrial touch screen is used for the operation, control and process monitoring of the entire system.

It can be seen from the above-mentioned technical solution provided by the present invention that the force position servo control system provided by the present invention to realize the automatic cleaning of the anode carbon block and carbon bowl for aluminum electrolysis includes a programmable controller, and the programmable controller is connected through the field bus. It communicates with five servo drive motors and is connected with the pressure sensor and torque sensor through the I/O port; it also includes a photoelectric switch installed at the starting position and end position of the carbon block for positioning the carbon block; it also includes A visual system for positioning the center of the carbon bowl and the angle of the chute of the carbon block; the programmable controller controls the cutter to clean the carbon bowl and the chute at the same time according to the positioning of the carbon bowl and the chute of the carbon block. After the positioning of the anode carbon block is completed, the height measurement of the carbon block, the positioning of the carbon bowl and the chute, and the cleaning of the carbon bowl and the chute are automatically completed, while ensuring that the chute is not damaged, and the carbon particles inside the carbon bowl are cleaned up to meet industrial requirements. , The cleaning efficiency of carbon blocks is guaranteed to be 300 blocks/day, which fully meets the daily output requirements of the production workshop.

Description of drawings

Fig. 1 is the schematic diagram of the principle of the force position servo control system that realizes the automatic cleaning of the anode carbon block carbon bowl for aluminum electrolysis provided by the embodiment of the present invention;

Fig. 2 is a schematic general diagram of the structure of the charcoal bowl cleaning system in the present invention;

Fig. 3 is a schematic diagram of cutter structure in the present invention;

Figure 4a is a schematic diagram of the anode carbon block in the present invention;

Figure 4b is a schematic diagram of the charcoal bowl in the present invention;

Fig. 5 is a flow chart of the force position servo control system of the present invention;

Fig. 6 is a flow chart of the carbon block height measurement signal in the present invention;

Fig. 7 is the flow chart of charcoal bowl center positioning signal in the present invention;

Fig. 8 is a flow chart of signals for cleaning the charcoal bowl in the present invention.

In the figure: 1. Roller installation position, 2. Carbon block cleaning position, 3. Third photoelectric switch emission and second photoelectric switch reception installation position, 4. Tool, 5. X-axis guide rail, 6. Z-axis guide rail, 7. Z-axis servo motor, 8. Y-axis guide rail, 9. Y-axis servo motor, 10. Signal light installation position, 11. X-axis servo motor, 12. Clamping motor, 13. The third photoelectric switch receiving and the second photoelectric Switch launch position, 14, main shaft (M-axis) servo motor, 15, chute motor, 16, pressure sensor, 17, torque sensor, 18, second cutter head, 19, first cutter head, 20, first charcoal bowl , 21, the second charcoal bowl, 22, the third charcoal bowl, 23, the fourth charcoal bowl, 24, the chute, 25, the charcoal bowl step surface, 26, the anode charcoal block charcoal bowl, 27, the anode charcoal block.

Detailed ways

The force position servo control system of the present invention realizes the automatic cleaning of the anode carbon block carbon bowl for aluminum electrolysis, realizes the fully automatic cycle operation, fault diagnosis and protection functions of the carbon bowl cleaning system, and uses a special control system and control method to realize its functions . The control system combines image recognition technology and field bus technology to solve the problem of charcoal bowl coordinate identification and positioning. At the same time, the cutting force measurement component is used to realize the mixed control of the force and position of the charcoal bowl cleaning tool. Simultaneous cleaning of the chute, while the force measurement component also provides monitoring data for fault diagnosis and self-protection of the cleaning process. The system realizes all the process control, motion control and force feedback control algorithms through the PLC control unit. For the first time, the automatic cleaning of the electrolytic anode carbon bowl is realized by the method of spindle cutter milling and inclined groove cutter simultaneous cutting. The case where the carbon particles in the bowl have a high bonding hardness can also be completely cleaned.

Embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The force position servo control system for realizing the automatic cleaning of the anode carbon block carbon bowl for aluminum electrolysis of the present invention, its preferred specific implementation is as shown in Figure 1:

Consists of five servo drive motors with absolute encoders, two pressure sensors, a torque sensor and a programmable controller that communicates with five servo drive motors via fieldbus and connects with pressure sensors and torque sensors through I/O ports device PLC. Its characteristics are: the anode carbon block is positioned by installing a photoelectric switch at the starting position and end position of the workpiece through the first device and the second device → positioning the center of the carbon bowl and the angle of the chute of the anode carbon block through the visual system → aligning the anode The actual height of the carbon block is measured → the PLC search algorithm accurately locates the carbon bowl and the chute of the anode carbon block → the cutter cleans the carbon bowl and the chute at the same time.

The first device is installed at the starting position of the carbon block, and sends a signal to the control system for the preparation of the carbon block; the second device is installed at the end position of the carbon block, and sends a signal to the control system for the presence of the carbon block.

There are a plurality of photoelectric switches at the second device.

When the carbon block does not reach the start or end position, the photoelectric switch is mistriggered due to the harsh environment on site, which will not cause malfunction of the mechanical system.

The positioning of the carbon bowl and the chute adopts dual positioning of the robot vision system and the PLC search algorithm.

The communication mode between robot vision system and PLC adopts RS232.

Searching for the position of the charcoal bowl, when the second cutter head enters the charcoal bowl is a sign signal of completion, that is, whether the difference between the current Z-axis encoder value and the value of the Z-axis servo motor encoder when the first cutter head reaches the upper surface of the carbon block is greater than a certain value value.

The control system uses the click method to search for the position of the charcoal bowl, that is, every time the tool moves a certain distance, click down once to determine whether it reaches the center of the charcoal bowl.

The warning judgment of the control system for the carbon bowl search is that the force feedback of the pressure sensor exceeds the limit.

The judgment of the specific search range is the maximum error allowed by the system in the X-axis direction and the Y-axis direction.

The control system judges the Y-axis direction of the charcoal bowl search through the pressure sensor when the first cutter head is in contact with the surface of the carbon block, and the force feedback of the two pressure sensors is different.

The measurement of the height of the carbon block is determined by the Z-axis encoder value when the tool is in contact with the upper surface of the carbon block.

The judging that the height of the carbon block is in place is judged by the force feedback value of the two pressure sensors exceeding the limit value when the carbon bowl is cleaned.

During height measurement, the spindle servo motor drives the first cutter head to rotate in torque mode to remove the carbon particles on the surface of the carbon block.

During searching the chute, the second cutter head maintains a certain contact force with the step surface of the charcoal bowl.

The realization of maintaining the contact force is that the force feedback of the pressure sensor is used as the input of the PID, and the output of the PID is the position of the second cutter head in the vertical direction.

The periodic pulse mode of PID is triggered, and the relative displacement of the second cutter head in the vertical direction is output.

During the search of the chute, the A-axis servo motor drives the second cutter head to rotate in torque mode, and at the same time controls the vertical position of the second cutter head through the force feedback of the torque sensor, that is, the position of the tool in the Z-axis direction.

During the search for the chute, it is judged whether the second cutting head reaches the top of the chute through the force feedback of the pressure sensor.

During the search for the chute, the control system PLC issues a warning in case the force feedback from the pressure sensor exceeds the limit.

The warning issued by the control system can be displayed on the alarm indicator light, touch screen and alarm buzzer on the panel of the control cabinet.

Clean up the charcoal particles inside the charcoal bowl and in the charcoal bowl chute to be cleaned at the same time.

The position control method of the carbon bowl chute is PID servo control.

The input of the PID servo control is the force feedback of the torque sensor, and the output is the relative displacement of the movement of the second cutter head inside the chute.

The force fed back by the torque sensor is the horizontal tangential force suffered by the six blades of the second cutter head.

The space helix that the second cutter head moves in conformity with the shape of the chute during the cleaning of the carbon bowl is realized by adjusting the angle of the second cutter head through the PID of the control system.

After finding the position of the carbon bowl and the chute, the control system will draw up an ideal planning curve for the position and shape of the carbon bowl and the chute.

The control system fits the horizontal and vertical movement of the second cutter head with the ideal planning curve, allowing a certain error.

Specifically, the damage control system of the charcoal bowl is comprehensively compared and judged according to the force feedback of the pressure sensor and the torque sensor and the force feedback during normal cleaning.

Whether the first cutter head reaches the bottom of the carbon bowl is judged by the force feedback value of the pressure sensor exceeding the preset value and the current Z-axis encoder value and the value of the Z-axis servo motor encoder when the first cutter head reaches the upper surface of the carbon block. The difference is greater than the preset value.

The control object of the present invention is mainly the cutter system of the carbon bowl cleaning system. While realizing the carbon block cleaning function, the control system also endows the carbon bowl cleaning system with comprehensive automatic operation capabilities. It can overcome the high surface temperature of the anode carbon block, the irregular shape of the carbon bowl, the randomness of carbon particles adhering to the surface of the carbon block and the inside of the carbon bowl, strong electromagnetic interference, high pollution and conductivity of carbon powder in the production of anode carbon blocks The impact of adverse factors such as sex on the control system. It overcomes the deficiencies in the prior art, such as large investment of manpower, great harm to human health, low production efficiency, high cost, great influence by subjective factors, and environmental pollution; the present invention provides a strict and efficient, low-input, high-output, No environmental pollution, convenient operation, high degree of automation, no need for professionals, and a control system that can completely monitor the cleaning of the anode carbon block and carbon bowl through the man-machine interface.

In the present invention, the PLC system loads the control algorithm program, through the established process, according to the information fed back by the sensor, sends instructions to the servo motor to control the operation and stop of the servo motor;

The human-machine interface system and the PLC system generate interactive information to complete operations such as status monitoring, default value modification, manual operation, and fault handling of the control system.

Among them, the communication mode between PLC and five servo drive motors is Canopen bus;

The data collected by the torque sensor and the pressure sensor are transmitted to the PLC through the I/O data acquisition module of the PLC;

The main technologies used in the system are servo motor control technology, pressure measurement technology, torque measurement technology, I/O data acquisition technology, I/O data filtering technology, data time domain analysis technology and PID control technology, etc. and anode carbon block process production The cleaning control scheme combined with the assembly line; the search range of the PLC automatic search program scheme is the maximum error of the error of the center coordinate of the anode carbon bowl and the angular coordinate of the chute fed back by the vision system.

The following describes how to measure the height of the carbon block, the center positioning of the carbon bowl, the positioning of the chute, and the cleaning of the carbon bowl and the chute:

Carbon block height measurement: There are some carbon particles on the upper surface of the anode carbon block, which has a certain hardness and adhesion. Before cleaning the carbon bowl of the anode carbon block, first move the cutter to the top of the anode carbon block, and use the absolute encoder that comes with the Z-axis servo motor to record the position of the cutter on the Z-axis at any time. The Z-axis descends and starts the torque mode of the spindle servo motor at the same time, so that the first cutter head rotates with a certain torque. When the cutter contacts the surface of the anode carbon block, the first cutter head can remove the adhered carbon particles on the surface of the anode carbon block. , determine whether the cutter has reached the actual carbon block surface by the measured values of the two pressure sensors on the upper part of the cutter. The adoption of this scheme is to consider that the tool system itself has a certain degree of flexibility, and the flexibility of the tool can protect the tool head and pressure sensor from damage under normal circumstances; With very high data, in the case of the flexibility of the cutter itself, even if the Z-axis has dropped to the theoretical depth of the carbon bowl, the cutter head of the cutter still cannot reach the bottom of the carbon bowl, and the carbon particles inside the carbon bowl cannot be completely cleaned.

Center positioning of the carbon bowl: the initial position of the cutter is the coordinate position given by the vision system; to search for the anode carbon block carbon bowl, judge the situation that the second cutter head enters the carbon bowl through the current value peak change of the pressure sensor on both sides of the cutter: (The first cutter head has a certain margin compared with the charcoal bowl. Even if there is a certain error in the positioning of the charcoal block, it can still enter the charcoal bowl.) The second cutter head must enter the charcoal bowl, and its positioning accuracy needs to reach 2mm; according to the carbon block The positioning error (generally about 6mm in the X-axis direction and about 4mm in the Y-axis direction); the cutting tool descends according to the predetermined position of the carbon bowl of the anode carbon block. At this time, there are two algorithms: one is that the second cutter head enters the carbon bowl If it is above 8mm, it means that the second cutter head enters the charcoal bowl and starts to search for the chute; secondly, the depth of the second cutter head penetrating into the charcoal bowl is less than 8mm; the search program is triggered, and the charcoal bowl is searched in the X-axis direction to click The center of the carbon bowl is searched by the method, that is, it is carried out step by step with a certain step length. When the position of the center of the carbon bowl in the X-axis direction is not reached, the difference in the values of the two pressure sensors above the tool caused by clicking on the carbon block will not be too large. Larger or keep a fixed difference, accurate judgment can be obtained by observing the time-domain fluctuation curve formed by filtering the output data of the two pressure sensors; when reaching the X-axis position of the center of the carbon bowl, according to the output data In the time-domain fluctuation curve formed after filtering, the changes of the two pressure sensors are significantly different, from which it can be inferred whether the position error of the second cutter head is in the positive or negative direction of the Y-axis; when searching for the Y-axis direction , with a smaller step size, click Search to find the center of the charcoal bowl;

Search for the chute of the anode carbon block: the second cutter head enters the carbon bowl for about 8mm, and it is necessary to find the position of the chute on the step surface inside the carbon bowl, and the second cutter head is pressed on the step surface (the pressure is guaranteed to be within within a certain range), in this process, the output of the two pressure sensors is used as the input of the PID control algorithm, and then the output of the PID algorithm is used as the displacement of the Z-axis position micro-adjustment, so that the second cutter head and the charcoal bowl step surface The purpose of maintaining the contact force; at the same time, the second cutter head is rotated with a certain torque, and when encountering larger adhered carbon particles, the speed of the second cutter head is reduced, and the Z-axis lifts the tool while maintaining the second cutter head at a certain The pressure is pressed on the step surface until the six blades of the second cutter head enter the chute.

Cleaning of the anode carbon block carbon bowl: After determining the center position of the carbon bowl and the angle of the chute, the cutter rises and exits the carbon bowl; keep the position unchanged, start the spindle servo motor, the first cutter head starts to rotate at a constant speed, start The tool is in the fast descending mode, approaching the carbon block; at a distance of 5mm from the carbon block, the Z-axis servo motor switches to the torque mode and begins to descend, at the same time start the force position servo control system of the chute servo motor and enter the chute; in the chute, The six blades of the second cutter head will be subjected to the force in two directions, which are respectively: the force in the vertical direction and the lateral force on the blade. Do separate measurement and monitoring, it and the sum of the force received by the first cutter head when cleaning the carbon particles inside the carbon bowl are reflected on the value changes of the two pressure sensors at the same time, when the output values of the two pressure sensors change too much, The cutter stops falling and rises to a certain height to protect the cutter head and pressure sensor; the lateral force on the blade is a force that needs to be strictly controlled; considering that the width of the carbon bowl chute is 4mm larger than the width of the blade, the force position is controlled by servo The goal is that the blade is only subjected to the force in the vertical direction, and the lateral force is zero; however, the six chute technology of the charcoal bowl is distributed spirally in space on the inner surface of the charcoal bowl, and the six blades of the second cutter head should be considered When reaching the bottom of the charcoal bowl, it is inevitable to contact the inner wall of the chute to generate a tangential force forming a circle with the six blades. The tangential force on the second cutter head can be directly measured by the torque sensor. Once it exceeds the normal rotation The required torque will trigger the chute servo motor to adjust the position of the second cutter head. The direction of the position adjustment is the same as the direction of the tangential force. The adjustment is based on the change of the tangential force measured by the torque sensor as the input of the PID control algorithm. The output of the PID control algorithm is the rotation angle of the second cutter head, and the cumulative maximum value of this angle will not exceed the difference between the inclined groove and the blade; this adjustment is carried out in real time, and it can be said that the second cutter head is in this mode Below, it is in a state of dynamic balance, and it is this state of dynamic balance that makes the movement trajectory of the blade of the second cutter head when cleaning the charcoal bowl and the chute be a space spiral curve that conforms to the chute process. Thereby it is ensured that the cleaning effect of the charcoal bowl and the chute meets the requirements.

The effect that the present invention can achieve is: after the positioning of the anode carbon block is completed, tasks such as height measurement of the carbon block, positioning of the carbon bowl and the chute, and cleaning of the carbon bowl and the chute are automatically completed, while ensuring that the chute and the carbon bowl are not damaged The cleaning of internal carbon particles meets industrial requirements, and the cleaning efficiency of carbon blocks is guaranteed to be 300 pieces per day to fully meet the daily output requirements of the production workshop.

Below in conjunction with accompanying drawing, the embodiment of the present invention is described in further detail as follows:

As shown in Figure 2, Figure 3, Figure 4a, and Figure 4b, the carbon bowl cleaning system is installed on the anode carbon block 27 production line, and the produced carbon block 27 is directly processed. First, the system notifies the push through the signal lamp 10 Carbon block 27, signal lamp 10 has two lamps: green is to push into carbon block signal, and red light is to begin to clean up anode carbon block signal, and signal lamp 10 carries buzzer, sends waiting signal. The production line pushes the anode carbon block 27 into the carbon bowl cleaning system to control the conveying device, the first photoelectric switch checks the carbon block 27, starts the raceway motor, and sends the carbon block 27 to the cleaning position 2. In order to ensure the accurate positioning of the carbon block, a brake is installed for the motor of the conveying device, and two pairs of photoelectric switches—the second photoelectric switch and the third photoelectric switch are used; the carbon block 27 first reaches the position of the second photoelectric switch, and the PLC detects the second photoelectric switch Switch starts, and sends stop instruction to raceway motor, detects the state of the 3rd photoelectric switch simultaneously, and the state of the 3rd photoelectric switch can be directly relevant with the initial position of anode carbon block carbon bowl 26. The positions of the two photoelectric switches differ by a certain distance, and their state can ensure the position error of the carbon block 27 within the allowable range; the PLC controls the clamping motor 12 to clamp the carbon block 27, and the X-axis servo motor 11 drives the tool 4 along the The positive direction of the X-axis moves in three steps to take pictures of the four charcoal bowls 26 (the initial position can be the first charcoal bowl 20); the PLC communicates with the vision system through the serial port, and the vision system is responsible for taking pictures and calculating the coordinates of each charcoal bowl. And send it to PLC, PLC determines the predetermined position of each charcoal bowl according to the received coordinates, and the coordinate error sent by the vision system is generally ±3mm.

As the flow chart shown in accompanying drawing 5, Fig. 6, at first cutter 4 is moved to the central position of two charcoal bowls 26, starts pressure sensor 16 protection programs, and this program is divided into two kinds: one, for correctly measuring carbon block 27 heights Algorithm, when the output of the pressure sensor 16 reaches the range of the set pressure value of this mode, the first cutter head 19, the cutter 4, the pressure sensor 16, and the guide rail can all work normally, and the height of the carbon block can be measured correctly; The algorithm for protecting the cutter sensor 16 and the guide rail. When the output of the pressure sensor 16 reaches the range of the set pressure value of this mode, the first cutter head 19, the cutter 4, the pressure sensor 16 and the guide rail may break down, and the measured height of the carbon block 27 is out of order. Low; the pressure ranges of these two modes are determined according to the range of the pressure sensor 16 and the variation range of the pressure sensor 16 during the cleaning process. The output value of the pressure sensor 16 mentioned here refers to the two pressure sensors 16 above the tool 4 Single and overall, that is, the output of the pressure sensor 16 does not exceed the specified range not only means that the output of the single pressure sensor 16 does not exceed the specified range, but also requires that the output sum of the pressure sensors 16 does not exceed the specified range; considering that the tool 4 is a rigid component, the first A cutter head 19 takes fast approaching with the contact of carbon block, and slow contact, starts main shaft servomotor 14 torque patterns simultaneously, and first cutter head 19 starts to rotate, can remove most carbon particles on the surface of anode carbon block 27. After the first cutter head 19 pressed the carbon block, the output of the pressure sensor 19 jumped, and the PLC recorded the current Z-axis servo motor 7 encoder value as the height of the carbon block 27. At the same time, the Z-axis guide rail 6 rose to move the first The cutter head 19 is separated from the carbon block 27 . The height of the carbon block 27 measured by this method needs to be corrected when judging the positioning of the carbon bowl, because the PLC judges the situation that the cutter head enters the carbon bowl according to the displacement of the Z axis, and the correction is to remove the gap caused by the cutter 4 itself. Flexible deformation, the error caused by the downward displacement of the cutter head.

As the flow chart shown in accompanying drawing 7, after determining the height of the anode carbon block 27, according to the coordinate position provided by the vision system, the PLC controls the servo motor to move the cutter 4 to the center coordinate position of the fourth carbon bowl 23, and adjusts the first cutter head 19 The direction of the two blades is the direction of the X-axis guide rail 5; start the force protection mode of the pressure sensor 16, and at the same time the Z-axis drops rapidly, approaching the anode carbon block 27, and at a certain distance from the surface of the anode carbon block 1, the Z-axis switches to the slow mode , ready to enter the anode carbon block carbon bowl 26, during the Z-axis descending process, the PLC will judge whether the first cutter head 19 and the second cutter head 18 enter the carbon bowl 26 and the chute 24, and whether they meet the conditions for normal cleaning of the carbon bowl 26 There are three main judging criteria in the charcoal bowl 26 search main program: 1, whether the first cutter head 19 enters the charcoal bowl 26; 2, whether the second cutter head 18 enters the charcoal bowl 26; 3, the second cutter head 18 Whether six blades enter chute 24. The PLC judges these three as the displacement of the Z-axis relative to the height of the corrected carbon block. For example, when the current position of the Z-axis 6 is less than 30mm relative to the height of the corrected carbon block, it is considered that the second cutter head Six blades of 18 have entered chute 24, and the location of charcoal bowl 26 has been completed.

For the judgment 1 in the main program of positioning the charcoal bowl 26, the two blades of the first cutter head 19 are in the direction of the X axis 5, so the error of the tool 4 in the Y direction can be ignored, as long as the position of the tool 4 is in the direction of the X axis 5, the error is within Within the error range, the first cutter head 19 can enter the charcoal bowl 26. At the same time, in order to ensure the cleanability of the charcoal bowl 26, a search program is also designed for the first cutter head 19. First, the cutter 4 is moved along the negative direction of the X axis 5 Move to the limit position of the coordinate error of the charcoal bowl, and start searching from this position. Every time a step is moved, the first cutter head (19) is clicked down once. After each click is completed, the Z-axis 6 rises rapidly to prevent pressure The sensor 16 exceeds the limit; if the Z-axis 6 descends a certain distance below the height of the carbon block, it is considered that the first cutter head 18 enters the carbon bowl. The total number of steps between the positive and negative limit positions is determined. If the number of search steps exceeds the total number of steps, it is considered that the charcoal bowl is damaged and the charcoal bowl cannot be searched.

For the judgment 2 in the charcoal bowl 26 positioning main program, if the displacement of the first cutterhead 18 entering the charcoal bowl 26 exceeds 25mm, (the vertical distance between the first cutterhead 19 and the second cutterhead 18 is 15mm), then it is considered that the first The second cutter head 19 also enters the charcoal bowl 26; if it cannot enter the charcoal bowl 26, start the second cutter head 18 search program, first the Z-axis 6 rises, and moves the cutter 4 to the error limit position of the second cutter head 18 or the first cutter The head enters the initial position of the charcoal bowl, and at the same time, the second cutter head 18 is rotated so that one pair of blades is parallel to the direction of the Y axis 8, and the search for the charcoal bowl 26 is started. Every time a step is moved, the second cutter head (19) clicks down once , after each click is completed, the Z-axis 6 rises rapidly to prevent the pressure sensor 16 from overrunning; after each click is completed, the change curve of the two pressure sensors 16 and the depth of the second cutter head 19 penetrating into the charcoal bowl are analyzed by the PLC , if it conforms to the characteristics of the specific change curve, and the penetration depth does not meet the requirements, it is considered that the second cutter head reaches the center position of the carbon bowl in the X-axis 5 direction, but there is still a positioning error in the Y-axis 8 direction. By analyzing the change curves of the two pressure sensors 16, the error direction of the second cutter head 18 can be obtained, and at the same time withdraw from the charcoal bowl 26, and move a step in the Y-axis 8 direction; click on the carbon block 27 again; until the second cutter The depth at which the head 19 penetrates into the charcoal bowl 27 satisfies the condition; the error ranges of the X-axis 5 and the Y-axis 8 are determined, so their respective total search steps are definite, and reaching the total search steps still does not meet the requirements for entering the charcoal bowl 26. condition, then it is considered that the charcoal bowl 26 is damaged, and the charcoal bowl 26 cannot be searched.

For the judgment 3 in the charcoal bowl 26 positioning main program, if the Z-axis 6 descending position is lower than the height of the carbon block 27 by 35mm, then it is considered that the six blades of the second cutter head 18 enter the chute 24; otherwise, the chute 24 search program is started; Start the PID first adjustment, the PID adjustment is based on the output of the pressure sensor 16 as the input, and the relative displacement that the Z axis 6 needs to move is the output, and the real-time monitoring adjustment is carried out; Triggered when the blade presses against the step surface 25 of the charcoal bowl 26; the chute motor 15 starts in torque mode and drives the second cutter head 18 to rotate counterclockwise; at this time, if the second cutter head 18 stops rotating, it means that it has encountered Larger carbon particles, now the Z-axis 6 rises, the second cutter head 18 starts to rotate again, and at the same time, the first PID adjustment impels the Z-axis 6 to descend to maintain the pressure value with the step surface 25; until the second cutter head 18 is found Six blades enter the chute; the search range of the second cutter head 18 is 70 degrees, and the second cutter head 18 still fails to enter the chute 24 after turning 70 degrees, then it is considered that the charcoal bowl 26 is damaged and cannot enter the chute 24; The blade is determined to enter the chute 24, the PID first adjustment is closed, and at the same time record the current X-axis 5, Y-axis 8 positions, the encoder position of the chute motor 15 (the position of the chute 24), and then the Z-axis 6 rises, the second The second knife head 18 exits the charcoal bowl 26.

As the flow chart shown in accompanying drawing 8, after determining the position of the carbon bowl and the chute of the anode carbon block, the measured X-axis 5Y-axis 8 coordinates also need to be corrected. Considering that the diameter of the carbon bowl 26 is larger than that of the second cutter head, the single Direction search into the carbon bowl 26 can not reach the center position of the charcoal bowl 26, so the coordinates of the measured center position need to be corrected; the correction value is based on the Y-axis and X-axis movement steps and the empirical value of the experiment. The second adjustment of PID is started, and the PID adjustment takes the variation of the output value of the torque sensor 17 as the input, and the displacement adjustment of the second cutter head 18 as the output. This adjustment can reflect the side force that the six blades of the second cutter head 18 are subjected to to the position adjustment of the second cutter head 18 in real time; the collection of the output data of the torque sensor 17 is not always carried out, but Collect once every 20ms, if the output of the torque sensor 17 meets the adjustment requirements, then drive the second cutter head 18 to move the corresponding displacement, otherwise the PID is in the monitoring state; the main shaft servo motor 14 drives the first cutter head 19 to start rotating, responsible for cleaning the charcoal bowl 26 internal carbon particles; the Z-axis 6 descends, and the six blades of the second cutter head 18 begin to enter the chute 24. At this time, there are two adjustments: the first adjustment is the PID second adjustment; the second adjustment is the pressure sensor 16 Output adjustment; for the first adjustment, if the torque sensor 17 numerical value increases (decreases), and exceeds the dead zone range of PID adjustment, then counterclockwise (clockwise) adjusts a certain angle of the blade of the second cutter head 18; for the second Adjustment, if the single or overall value of the pressure sensor 16 exceeds the limit value, it will trigger the Z-axis 6 rewinding action to protect the sensor on the cutter head and the tool; the first adjustment, the second adjustment and the Z-axis drop are valid. The condition is that the cutter head does not reach the bottom of the charcoal bowl 26; once it reaches the bottom of the charcoal bowl 26, it will trigger the quick exit charcoal bowl program of the cutter 4; when exiting the charcoal bowl 26, the PID second adjustment will not be closed until the second knife Head 18 leaves charcoal bowl 26, then, starts the cleaning of the third charcoal bowl 22.

Before positioning the third carbon bowl 22, the PLC will comprehensively compare the actual cleaning position of the fourth carbon bowl 23 and the preset position of the third carbon bowl 22 according to the design position of the carbon bowl of the anode carbon block 27, and select one of them One as the center position of the third charcoal bowl 22, cutter 4 is moved to this position, under normal circumstances, cutter 4 does not need to search again, just can directly enter the 3rd charcoal bowl 26, starts the program of cleaning charcoal bowl 26; But If the charcoal block 27 has a relatively large deformation when roasting, then it needs to be searched, but the position error of the charcoal bowl 27 has been greatly reduced. Start the same search program as the fourth charcoal bowl to complete the third charcoal bowl 22 The cleaning tasks of the second charcoal bowl 21 and the first charcoal bowl 20; at this moment, the PLC controls the clamping motor 12 to loosen the charcoal block 26; When the road motor transported the next charcoal bowl 26, the charcoal block 26 that had been cleaned was also transported out.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field can easily conceive of changes or changes within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (8)

1. power Positioning Servo System that realizes anode carbon block for aluminium electrolysis charcoal bowl automation cleaning, comprise five servomotors that carry absolute encoder, two pressure sensors, torque sensor and visual identity software and hardware system, described five servomotors that carry absolute encoder are respectively spindle servo electric machine, skewed slot servomotor, X-axis servomotor, Y-axis servomotor, Z axis servomotor, it is characterized in that:

Also comprise Programmable Logic Controller, described Programmable Logic Controller is communicated by letter, also by the I/O port, with described pressure sensor, with torque sensor, is connected with five servomotors that carry absolute encoder by fieldbus; X-axis servomotor, Y-axis servomotor, Z axis servomotor in five servomotors that carry absolute encoder form the three degrees of freedom right angle coordinate robot system, be used for carrying the cleaning cutter and realize location, all the other two two kinds of tool motions on the cleaning cutter being controlled respectively;

Also comprise that the original position and the final position that are arranged on the charcoal piece are used for the optoelectronic switch that the charcoal piece is positioned;

Described visual identity software and hardware system comprises the vision system to charcoal piece De Tanwan center and angle of bevel location;

Can control cutter by power Position Hybrid Control method clears up simultaneously to charcoal bowl and skewed slot;

Working angles limits the pressure of vertical direction and the torsion of skewed slot cutter, closed loop PID control by torsion and the motion of skewed slot cutter has been realized the power Position Hybrid Control, make the skewed slot cutter can be in cutting decline process, automatically rotate cleaning when realizing charcoal bowl and skewed slot along the hand of spiral of skewed slot.

2. the power Positioning Servo System that realizes anode carbon block for aluminium electrolysis charcoal bowl automation cleaning according to claim 1 is characterized in that:

The optoelectronic switch that is arranged on charcoal piece final position has two, for detection of the charcoal piece, puts in place and leaves with the charcoal piece, realizes doing coordinating of mode with the original production lineman.

3. the power Positioning Servo System that realizes anode carbon block for aluminium electrolysis charcoal bowl automation cleaning according to claim 1 is characterized in that:

Determine employing vision system and the image recognition software of Tan Wan center and angle of bevel position obtain coordinate, then with the motor of the described three degrees of freedom right angle coordinate of Controlled by Programmable Controller robot, carry out tool setting search realization.

4. according to claim 1 or 3 described power Positioning Servo System that realize anode carbon block for aluminium electrolysis charcoal bowl automation cleaning is characterized in that:

Vision system obtains charcoal bowl coordinate time single charcoal bowl is taken pictures respectively, obtains the relative coordinate of charcoal bowl, then take encoder for servo motor numerical value as reference, calculates absolute coordinate.

5. according to claim 1 or 3 described power Positioning Servo System that realize anode carbon block for aluminium electrolysis charcoal bowl automation cleaning is characterized in that:

Control system adopts the test method under the power restrictive condition to search for the position of charcoal bowl, be that cutter often moves and moves a step in search procedure, cutter test contact charcoal piece, and stop after reaching certain contact force, judge highly by pressing down whether cutter aims at Tan Wan center and skewed slot position.

6. the power Positioning Servo System that realizes anode carbon block for aluminium electrolysis charcoal bowl automation cleaning according to claim 5 is characterized in that:

During the physical location at Controlled by Programmable Controller three degrees of freedom right angle coordinate robot searches Tan Wan center, adopted a kind of grid type traversal search mode, i.e. grid division centered by coordinates computed, carry out tool setting with fixed step size in X and Y-direction and sound out.

7. the power Positioning Servo System that realizes anode carbon block for aluminium electrolysis charcoal bowl automation cleaning according to claim 1 is characterized in that:

The measurement of charcoal tile height is to utilize the method for cutter contact charcoal piece to realize, namely cutter presses down and read force sensor data, and when cutter contacted with charcoal piece upper surface, the encoder numerical value by the Z axis servomotor can access the charcoal tile height.

8. the power Positioning Servo System that realizes anode carbon block for aluminium electrolysis charcoal bowl automation cleaning according to claim 1 is characterized in that:

Have the dual touch screen operation interface, wherein touch industrial computer display screen is used for operation charcoal bowl image recognition software and monitors charcoal bowl situation, and graphic control panel is used for operation, control and the process monitoring of whole system.

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